(1) Field of the Invention
The present invention relates to a host system for a base station, and more particularly to a basestation host system for receiving ATM (Asynchronous Transfer Mode) cells of AAL (ATM Adaptation Layer) Type 2 from a base station.
(2) Description of the Related Art
Since ATM networks transfer all information as cells, layers (up to the ATM layer) involved in the transfer of cells do not process voice data, video data, and other data in consideration of media and services. Service qualities (delay times, error rates, etc.) required for respective services are different from each other. Therefore, for converting original information for the services into cells, it is necessary to absorb the difference between such different service qualities. ATM adaptation layers (AALs) are employed to meet such a requirement.
There are different types of ATM adaptation layers that are classified according to function. Recently, AAL Type 2 has been standardized. Efforts have been made to standardize AAL Type 2 for transferring voice data that have been compressed to less than 64Kbps. AAL Type 2 has been developed under the concept of multiplexing CPS (Common Part Sublayer) packets of plural users having short variable-length payloads into ATM cells.
AAL Type 2 serves to meet the strong demand in the market for applying the ATM technology to communications between radio base stations and switching offices of cellular mobile communication systems.
Inasmuch as the standardization of ATM communications of AAL Type 2 has just been completed, there has heretofore been available no system based on AAL Type 2.
FIG. 11 of the accompanying drawings shows in block form a mobile communication system to which ATM communications of AAL Type 2 are applied. As shown in FIG. 11, the mobile communication system has a plurality of base transceiver stations (BTS) 101-103 and a base station controller (BSC) 104. ATM communications of AAL Type 2 are applied to the transmission over entrance links between the base transceiver stations 101-103 and the base station controller 104. In the base station controller 104, CPS packets contained in ATM cells of AAL Type 2 are extracted, and routed using a packet switch (P-SW) 104a. 
The packet switch 104a buffers each packet, reads its address, and effects switching depending on the address. Such activities of the packet switch 104a are software-implemented. However, the software-based packet routing is slow and tends to put a large burden on the base station controller 104 which controls the packet switch 104a. 
For transmitting order wire service information, it is necessary to install separate dedicated lines between base transceiver stations 101-103 and the base station controller 104. However, since installing such separate dedicated lines entails an additional expenditure of expenses, there is a demand for an improved scheme for transmitting order wire service information without separate dedicated lines.
It is an object of the present invention to provide a base-station host system for achieving high-speed routing for ATM communications of AAL Type 2 to reduce a burden on a controller which carries out a routing process.
Another object of the present invention is to provide a base-station host system which is capable of transmitting order wire service information without separate dedicated lines.
To accomplish the above objects, there is provided a host system for controlling a base station to transmit a signal to and receive a signal from the base station by way of a cell containing a plurality of packets representing signals from the base station to a plurality of base station or from a plurality of base station to the base station, comprising packet extracting means for extracting a plurality of individual packets contained in a cell, cell generating means for generating an internally processable cell based on the individual packets extracted by the packet extracting means, switching means for switching internally processable cells generated by the cell generating means depending on routes thereof, packet generating means for generating packets based on an internally processable cell destined for a base station, and cell transmitting means for generating a cell containing a plurality of packets designed to the same base station from the packets which are generated by the packet generating means and transmitting the generated cell to the base station.
To accomplish the above objects, there is also provided a host system for controlling a plurality of base stations in a mobile communication system, comprising receiving means for receiving a cell carrying order wire service information from a base station, and transmitting means for adding order wire service information to a cell and transmitting the cell to a base station.
The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.